Soft contact lenses are one of several types of contact lenses for corrective vision eyewear as prescribed by optometrists and ophthalmologists.
Background
In the US market, soft contact lenses are approved by the US Food and Drug Administration. The American Optometric Association published a contact lens comparison chart called Advantages and Disadvantages of Various Types of Contact Lenses on the differences between them. These include: soft contact lenses rigid gas-permeable (RGP) daily wear extended wear disposable planned replacement contact lenses.
The US Food and Drug Administration (FDA) defines soft contact lenses as:
History The first contact lenses were made of glass, in 1888. Initially the glass was blown but soon lenses were made by being ground to shape. For the first fifty years, glass was the only material used. The lenses were thin, yet reports of injury were rare. In 1938 perspex (polymethylmethacrylate, or PMMA) began to replace glass in contact lens manufacture. PMMA lenses were easier to produce so the production of glass lenses soon ended. Lenses made of PMMA are called hard lenses. Soft contact lenses were first produced in 1961 by Czech chemical engineer Otto Wichterle using polyhydroxyethylmethacrylate (pHEMA), a material that achieved long-term commercial application. Lenses made of polyacrylamide were introduced in 1971.
Types The FDA classifies soft contact lenses into four groups for the US market. They are also subcategorized into 1st generation, 2nd generation, and 3rd generation lens materials. These 'water-loving' soft contact lens materials are categorized as "Conventional Hydrophilic Material Groups ("-filcon"): Group Water Content Percentage Ionic/Non-Ionic I Low Water Content (<50%) Nonionic II High Water Content (>50%) Nonionic III Low Water Content (<50%) Ionic IV High Water Content (>50%) Ionic Note: Being ionic in pH = 6.0 – 8.0.
The FDA has been considering updating soft contact lens group types and related guidance literature.
Contact lens polymers The materials that are classified in the 5 FDA groups include the ones listed in the next 5 sections:
+FDA classification of soft contact lens materialsFDA lens groupAdopted nameTransmissibility level (Dkx10)Water contentChemical compositionIgalyfilcon A6047%–lotrafilcon A14024%, siloxane, lotrafilcon B11033%polymacon7.536%tetrafilcon9.043.5%, , IIalphafilcon A22.966%, hilafilcon A26.970%omafilcon A19.662%, IIIbalafilcon A9936%, , , bufilcon A16.045%, , IVetafilcon A17.058%, ocufilcon D19.755%vifilcon A16.055%, , PVP
Hydrogel groups Below is a list of most contact lens materials on the market, their water percentage, their oxygen permeability rating, and manufacturer brands. Note that the higher the oxygen transmissibility rating, the more oxygen gets to the eye.
Low-water nonionic Material % Water Oxygen Transmissibility (Dk/t) Brands Tefilcon 38 8.9 Cibasoft, Illusions, Torisoft, Softint, STD, LL Bifocal Tetrafilcon A 43 9 Cooper Clear, Cooper Toric, Preference, Preference Toric, Vantage, Vantage Accents, Vantage Thin, Vantage Thin Accents Crofilcon 38 13 CSI, CSI Toric Helfilcon A/B 45 12 Continental Toric, Flexlens, Flexlens Toric, Flexlens Aphakic, Optima Toric, All X-Cel lenses Mafilcon 33 4 Menicon Polymacon 38.6 8.5–24.3 Allvue, Biomedics 38, Clearview, CustomEyes 38, EpconSOFT, EsstechPS, Esstech PSD, Esstech SV, Frequency 38, HD, HD-T, HDX, HDX-T, Horizon 38, Hydron Mini, Hydron Zero 4 SofBlue, Hydron Zero 6 SofBlue, Hydron Versa Scribe, Lifestyle MV2, Ideal Soft, Lifestyle Xtra, Lifestyle 4Vue, Lifestyle Toric Bifocal, LL38, Metrosoft ll Multifocal, Metrosoft Toric, Natural Touch, Occasions, Optima 38/SP, PS-45 Multifocal, Simulvue 38, Sof-form II, SofLens, SofLens38, SofLens Multi-Focal, Softics, SoftView, Unilens 38, Westhin Toric, EZvue Soft Contact Lens, Solotica Hioxifilcon B 49 15 Alden HP Sphere, Alden HP Toric, Aquaease, Essential Soft Toric Multifocal, Flexlens, Quattro, Satureyes, Satureyes Toric and Multifocal, All X-Cel Lenses
High-water nonionic Material % Water Oxygen Transmissibility (Dk/t) Brands Surfilcon A 74 35 Lidofilcon A 70 31 ActiFresh 400, CV 70 Lidofilcon B 79 38 Netrafilcon A 65 34.5 Hefilcon B 45 10 Optima Toric Alphafilcon A 66 32 SofLens Toric for Astigmatism Omafilcon A 58–60 28–36.7 Proclear 1-Day, Proclear EP, Proclear 1 day Multifocal, Proclear Multifocal Toric, Biomedics XC, Aveo Omafilcon B 62 21.3–52.3 Proclear Sphere, Proclear toric, Proclear toric XR, Proclear multifocal, Proclear multifocal XR, Proclear multifocal toric Vasurfilcon A 74 39.1 Precision UV Hioxifilcon A 59 28 Alden HP Sphere, Alden HP Toric, ExtremeH₂O 59% Thin/Extra, Biocurve Gold Sphere and Toric, Aura ADM, Scout by Warby Parker, Hydro by Hubble, Miru 1 Day, iWear slim, Atrea Select 1 day Hioxifilcon D 54 21 Alden HP Sphere, Alden HP Toric, ExtremeH₂O 54%, Clarity H₂0, C-Vue Advanced Custom Toric Nelfilcon A 69 26 Focus Dailies, Focus Dailies Toric/Progressive, Dailies AquaComfort Plus, FreshLook One-Day, Synergy, Triton, easyvision Vitrea Hilafilcon A 70 35 Hilafilcon B 59 22 SofLens 59, SofLens Daily Disposable, SofLens Daily Disposables for Astigmatism, easyvision Virision daily Acofilcon A 58 25.5 Flexlens Tricurve Keratoconus Nesofilcon A 78 42 Biotrue ONEday
Low-water ionic Material % Water Oxygen Transmissibility (Dk/t) Brands Bufilcon A 45 16 Hydrocurve II 45, Soft Mate B Deltafilcon A 43 10 Amsoft, Amsoft Thin, Comfort Flex, Custom Flex, Metrosoft, Soft Form Toric Phemfilcon 38 9 Durasoft 2
High-water ionic Material % Water Oxygen Transmissibility (Dk/t) Brands Bufilcon A 55 16 Hydrocurve I, Hydrocurve 3 Toric, Softmate II Perfilcon A 71 34 Permalens Etafilcon A 58 23.8–28 Acuvue, Acuvue Bifocal, Acuvue 2, Acuvue 2 Colors, 1-Day Acuvue, 1-Day Acuvue Moist, 1-Day Acuvue Moist for Astigmatism, 1-Day Acuvue Moist Multifocal, 1-Day Acuvue Define, Colornova, Discon, Waldo, Natural Vue, Ocylens Focofilcon A 55 16 Fre-Flex Ocufilcon B 52–53 16–24 ClearSight 1-Day, Continental, Ocu-Flex 53 Ocufilcon C 55 16 UCL55, UCL-Pediatric Ocufilcon D 55 17.8–28.1 Biomedics 55 Premier asphere, Biomedics Toric, ClearSight 1-Day Toric, Horien 1-Day Disposable, Cadence Comfort 1 Day, Flextime One Day, iWear fit, Ocean daily, Optosan One Ocufilcon E 65 22 Ocuflex 65 Ocufilcon F 60 24.3 Hydrogenics 60 UV Phemfilcon A 55 16 Durasoft 3, Freshlook, Wildeyes Methafilcon A 55 17.9-37.6 Biocurve Advanced Aspheric, Biocurve 1-Day, Biocurve Toric & Sphere, C-Vue 1-Day ASV, C-Vue 55, Edge III 55, Elite AC, Elite Daily, Elite AC Toric, Expressions Colors, Flexlens, Frequency 55 Sphere/Multifocal, HD2, HDX2, Horizon 55 Bi-Con, Hubble, Kontur, LL55, New Horizons, Revolution, Sauflon 55, Sof-form 55, Sunsoft Eclipse, Sunsoft Toric, Vertex Sphere, Vertex Toric, Atrea Blue 1 day Methafilcon B 55 14.5–31.3 Frequency 55 Toric, Hydrasoft Sphere, Hydrasoft Sphere Thin, Hydrasoft Aphakic, Hydrasoft Aphakic Thin, Hydrasoft Toric, Hydrasoft Toric Thin Vilfilcon A 55 16 Focus 1–2 Week Softcolors, Focus Monthly Softcolors, Focus Toric, Focus Progressives, Soft 55, Soft 55 EW
Silicone hydrogel polymers Material Company FDA Approval Replacement cycle % Water Oxygen Transmissibility (Dk/t) Modulus (MPa) Center Thickness (mm) Brands Lotrafilcon A Alcon 2001 monthly 24 175 1.5 0.08 Air Optix Night & Day Aqua, easyvision monthly aquaeyesSifilcon AAlcon200432820.08O2Optix Custom Lotrafilcon BAlcon 2011 monthly 33 110–138 1.0 0.08 O2Optix, Air Optix for Astigmatism, Air Optix Aqua, Air Optix Aqua Multifocal, Air Optix Colors, Air Optix plus HydraGlyde, Air Optix plus HydraGlyde Multifocal, Air Optix plus HydraGlyde for Astigmatism, Specsavers easyvision Irisian (plus), Oculsoft OxygenVerofilcon AAlcon2018daily51–80(water gradient)90-1000.60.09Precision1, Precision1 for AstigmatismLehfilcon AAlcon2021monthly55–99(water gradient)1540.60.08TOTAL30, TOTAL30 for Astigmatism, TOTAL30 MultifocalDelefilcon AAlcon2023daily33–99(water gradient)1560.70.09DAILIES TOTAL1, DAILIES TOTAL1 Multifocal, DAILIES TOTAL1 for AstigmatismBalafilcon ABausch & Lomb2005monthly3691-1301.10.09PureVision, PureVision Toric, PureVision Multi-Focal, PureVision2, PureVision2 for Astigmatism, PureVision2 Multi-Focal for PresbyopiaSamfilcon ABausch & Lomb2013monthly46163Lens Parameters pi.bausch.com Retrieved 30 March 20230.70.07Bausch & Lomb Ultra, Bausch & Lomb Ultra for Astigmatism, Bausch & Lomb Ultra for Presbyopia, Bausch + Lomb ULTRA Multifocal for Astigmatism, iWear intenseKalifilcon ABausch & Lomb2023daily551340.50.08Bausch & Lomb INFUSE, INFUSE for Astigmatism, INFUSE One-Day Multifocal, Bausch & Lomb ULTRA ONE DAY, Bausch & Lomb ULTRA ONE DAY MultifocalComfilcon ACooperVision2008monthly48116–1600.750.08Biofinity, Biofinity toric, Biofinity XR, Biofinity XR toric, Biofinity Energys, Biofinity multifocal, Ascend Premier, Cadence premier, Options premier, Atrea Excellence Plus, Atrea Excellence Pro, iWear oxygenRiofilcon ACooperVisiondaily58930.40.07Specsavers easyvision AquianeEnfilcon ACooperVision2012monthly461000.60.06Avaira, Avaira Toric, Specsavers easyvision Monthly UviciaFanfilcon ACooperVision2016monthly5590–1100.60.06Avaira Vitality, Avaira Vitality toric, ascend evolve+, options evolve+, 24H Toric, Atrea Comfort 1 Month, iWear balance plus, easyvision Uvicia PlusStenfilcon ACooperVision2020daily5480–1000.40.08MyDay, MyDay toric, MyDay Multifocal, MyDay Energys, Kirkland Signature, Specsavers easyvision Linarial, iWear harmony, Atrea Excellence 1 day, Atrea Excellence Pro 1 day, TrueLens Platinum DailySomofilcon ACooperVision2020daily + monthly5657–860.50.07clariti 1 day, clariti 1 day toric, clariti 1 day multifocal, Live daily disposable, clariti elite, clariti toric, clariti xr toric, clariti multifocal, ascend 1 Day Air, easyvision Umere, easyvision Sential, iWear activ, iWear Vivid, TrueLens Premium Daily, aquaclear aironeInofilcon AInterrojo2026daily + monthly4577-1060.068Clalen o2o2 1-Day, Clalen o2o2 1-Day Toric, Clalen o2o2 1-Day Multifocal Galyfilcon AJohnson & Johnson 2003 monthly 47 86 0.43 0.07 Acuvue Advance with Hydraclear, Acuvue Advance for Astigmatism Senofilcon AJohnson & Johnson 2004 daily + biweekly 38 103–147 0.7 0.07 Acuvue Oasys, Acuvue Oasys for Astigmatism, Acuvue Oasys for Presbyopia, Acuvue Oasys 1-Day, Acuvue Oasys 1-Day for Astigmatism, Acuvue Oasys with Transitions, Acuvue Oasys Max 1-Day, Acuvue Oasys Max 1-Day for Astigmatism, Acuvue Oasys Max 1-Day MultifocalNarafilcon AJohnson & Johnson2007daily461180.660.0851-Day Acuvue TruEye (new)Narafilcon BJohnson & Johnson2010daily48551-Day Acuvue TruEye (old) Senofilcon C Johnson & Johnson 2016monthly 41 129–147 0.77 0.07 Acuvue Vita, Acuvue Vita for AstigmatismAsmofilcon AMenicon2018monthly40161 0.9 0.08 Miru 1month Menicon, Miru 1month Menicon Toric, Miru 1month Menicon Multifocal, Atrea Excellence 1 Month, iWear connect, easyvision OrbaMidafilcon AMenicon2020daily5664 0.36 0.07 Miru 1day UpSide, Miru 1 Day UpSide Toric, Miru 1 Day UpSide Multifocal, Miru 1month Menicon Multifocal Toric, iWear Flex, easyvision SoriaElastofilconSilSoft19910.2340 SilSoft Aphakic, SilSoft Super PlusOlifilcon BVisco Vision2016daily47120 0.6 0.08 Kits Daily, Everclear Elite, Hubble SkyHyOlifilcon AVisco Vision2019monthly47150K183670 - Trade/Device Name: Vexillum Zephyr (olifilcon A) with Tangible Polymers Silicone Hydrogel Soft Contact Lenses 0.6 0.08 Everclear Plus, Everclear AirSerafilcon AAlcon2024weekly55Sphere: 149 Toric: 1190.60.08Precision 7, Precision 7 for Astigmatism, Lumiere 7, Lumiere 7 for Astigmatism
Production generations There are three generations of silicone hydrogel contact lens materials: